1. Field of the Invention
The invention relates to instruments for detecting forces and more specifically to an instrument utilizing a body of magnetic material whose position in a cavity changes in response to a vector component of an acceleration force or acceleration forces to which the instrument is subjected.
2. Description of the Prior Art
A prior art patent search was conducted prior to preparing this patent application. This search failed to reveal instruments for measuring acceleration forces using techniques similar to those utilized in the instrument which is the subject of this patent application. However, the following prior art patents illustrate an electronic carpenter's level and various applications of magnetic devices and techniques.
A level using an electrolyte to detect changes in the orientation of the level is illustrated in U.S. Pat. No. 4,654,977.
Devices in which a body of magnetic material is suspended in a cavity by a magnetic field are illustrated in U.S. Pat. No. 4,473,259. This patent also illustrates the use of a control system to adjust magnetic fields to maintain the body of magnetic material at the desired location within the cavity. In the specific embodiment, the device is used as a bearing with a rotating shaft suspended such that it does not mechanically contact any portion of the structure.
Devices for magnetically suspending bodies of magnetic materials are further illustrated in U.S. Pat. No. 4,273,054. The apparatus illustrated in this patent is primarily intended for use in levitating railroad cars. Magnetically levitated railroad cars are further illustrated in U.S Pat. No. 4,356,772. In addition to illustrating magnetic levitation, this patent illustrates methods and apparatus for damping oscillations in the levitated train.